Specimens from human ocular tissues with various diseases, such as uveitis, conjunctival and corneal diseases, and ocular metabolic genetic diseases and tumors, were studied using the immunoperoxidase technique and light and electron microscopic evaluation. In uveitis, immunocompetent cells and lymphokines are critical in the reflection of clinical diagnosis, disease course, and prognosis. In non-uveitis diseases, alteration of cellular membrane surface markers and intracytoskeleton on the ocular resident cells may imply damages and abnormalities in these diseases. The relationship between infiltrating inflammatory cells and other cells may play some significant roles in the clinical behavior of various diseases.